JP3508076B2 - Float pendulum type tilt angle sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type inclination angle sensor for detecting a change in magnetic flux based on an inclination angle by a magneto-electric conversion element in a non-contact manner and converting it into an electric signal, and particularly to an inexpensive structure. The present invention relates to a non-contact type tilt angle sensor that can be easily mounted on a printed wiring board.

[0002]

2. Description of the Related Art In a circuit for controlling a tilt angle of a vehicle body that rotates or rocks in the fields of traveling control of a land cruiser, an RV vehicle, etc., and a posture control of a construction civil engineering machine, etc., the tilt angle is magnetically non-contacted. It is important to generate a change in the magnetic flux based on the tilt angle and convert it into an accurate electric signal when attempting to detect and convert it into an electric signal by using various non-contact tilt angle sensors. Proposed.

For example, as an example of a conventional non-contact type inclination angle sensor, there is a non-contact type sensor unit according to Japanese Utility Model Laid-Open No. 3-40522 and its applied product, which is caused by a swing of a weight in damping oil. Although it is a weight pendulum type that detects the inclination angle, if a magnetoresistive element is used as the magnetoelectric conversion element for the detection means, the detection performance will improve, but inevitably the entire product will be expensive. . Therefore, it is required to use an inexpensive Hall element as the detecting means to reduce the product cost.
Therefore, an example of a conventional weight pendulum type tilt angle sensor using a Hall element as a detection means will be described.

3A and 3B are explanatory views schematically explaining a conventional rotation axis orthogonal type inclination angle sensor. FIG. 3A shows a cross section viewed from the front, and FIG. 3 shows a cross section viewed from the side surface in the direction of arrow ii-ii in 3 (a). In FIGS. 3A and 3B, the tilt angle sensor is supported by the rotating shafts 1 and 1 by the ball bearings and faces the magnet 3 that rotates coaxially with the swing of the weight 2 and the magnet 3. And the external lead terminals 5 connected to the magnetoelectric conversion element 4.

Further, the magnetic flux of the magnet is changed according to the inclination angle θ which is the inclination angle, the magnetic field strength of the changing magnetic flux is detected by the magnetoelectric conversion element 4 and converted into an electric signal, and the external lead terminals 5 ... By sending out, the inclination angle θ is detected in a non-contact manner. A Hall element is used as the magnetoelectric conversion element 4. In use, the weight 2 is placed vertically below the magnet 3 and the Hall element 4, and the external lead terminal 5 ...
5 is arranged vertically above the Hall element 4, and the inclination angle θ
Accordingly, the weight 2 is swung by gravity.
The inclination angle θ changes within a range in which it is distributed to the left and right 45 ° centering on the vertical line, so that the limit at which a civil engineering machine or the like starts to fall while moving on the ground can be detected in advance.

The external lead terminals 5 ...
6 are connected to each other via the wiring board 7, and in order to realize the connection by the shortest path and the downsizing of the wiring board 7, the magnet 3 which is the main part of the detection function is connected. It will be arranged vertically above the Hall element 4. The Hall element 4 is of a rotary axis orthogonal type in which the detection surface for receiving the magnetic flux is arranged orthogonal to the rotary axis 1, while the magnet 3
Are arranged in a direction in which a magnetic flux is generated parallel to the rotation axis 1, and the area facing the detection surface is changed according to the inclination angle θ. In use, for example, keep the printed wiring board 9 horizontal,
Since the inclination angle sensor is attached to this from vertically below, it is generally mounted on the solder surface of the printed wiring board 9. In addition to this, there is a rotary axis parallel type in which the hall element is arranged in parallel with the rotary axis, and which one is to be used is selected depending on the actual application.

FIG. 4 is an explanatory view for schematically explaining a conventional rotary axis parallel type tilt angle sensor. FIG. 4 (a) shows a cross section as viewed from the front, and FIG. 4 (b) shows the same. 4 (a) shows a cross section viewed from the side surface in the direction of arrow iii-iii in FIG. In FIG. 4A and FIG. 4B, this inclination angle sensor includes a detection surface of the Hall element 4 and the magnet 3
Are arranged parallel to each other, the Hall element 4 is mounted on the wiring board 7 by bending the four lead wires 6 ... 6, and the magnet 3 is arranged at a right angle to the rotation axis 1 in the direction of generating magnetic flux. There is.

3 except that the angle at which the magnetic flux penetrates the detection surface and the strength of the magnetic field change according to the inclination angle θ.
This is the same as the conventional example of the rotary axis orthogonal type in. As an actual application, in addition to the one shown in FIG. 4, for example, while keeping the four lead wires 6 ... 6 straight, wire them to the external lead terminals 5. Some of them are mounted on the printed wiring board 9 in the horizontal direction, and in this case, the printed wiring board 9 cannot be mounted on the other side. All of these methods utilize the gravity applied to the weight 2, and the heavier the weight 2, the higher the detection accuracy.

On the other hand, the gravitational force of the weight 2, etc.
Since 1 is subjected to a large load in the right-angled direction, the ball bearing needs an expensive one having high strength, but this has a mechanical limit. Therefore, it is necessary to make a compromise to balance these detection accuracy and load appropriately. On the other hand, in order to reduce the load applied to the ball bearings
The inclinometer according to Japanese Patent Laid-Open No. 7-34403 and Japanese Patent Laid-Open No. 7-49.
There is an angle sensor, an inclination detection device and the like according to Japanese Patent Laid-Open No. 63-63, and these technologies for reducing the weight by the buoyancy of the float are disclosed. The actual usage state including the mounting method has been described above, but in addition to these, there is one using a different casing that is mounted from above the printed wiring board 9 in the vertical direction.

FIG. 5 is an explanatory view for schematically explaining a conventional inclination angle sensor of a different casing, and FIG.
Shows a cross section viewed from the front, and FIG. 5 (b) is a plan view of FIG. 5 (a). In FIG. 5 (a), this inclination angle sensor has four long external lead terminals 12, ... At four corners of a large wiring board 11 on which the lead wires 6 ,. It is the same as the conventional example of the rotary shaft orthogonal type in FIG. 3 or the conventional rotary shaft parallel type in FIG. 4 except that it is housed in a new case 13 provided in the vertical direction. Four long external lead terminals 12 ... 1
2 is wired on the wiring board 11 with the respective lead wires 6 ... 6 and can be generally mounted on the component side of the printed wiring board 9 in a used state. However, this casing is characterized in that the entire structure is structurally large and the wiring path is long and complicated.

[0011]

However, when these conventional tilt angle sensors are used in an inexpensive structure to detect an accurate tilt angle, there are the following problems. (1) The weight pendulum type tilt angle sensor requires ball bearings and magnetoresistive elements, which are expensive parts, and therefore increases the overall product cost. (2) Although some large tilt angle sensors having different purposes use large floats, they are not suitable for applications that require miniaturization of the whole. (3) Further, since it is necessary to arrange the detecting means above the weight in the vertical direction, the inclination angle sensor itself must be mounted vertically below the printed wiring board or the printed wiring board itself must be mounted vertically. There wasn't. In view of the above problems, it is an object of the present invention to provide a float pendulum type tilt angle sensor having an inexpensive structure suitable for mounting a printed wiring board.

[0012]

In order to solve the above problems, the present invention has the following means. (1) A hollow float that floats in a liquid, a magnet supported by a rotating shaft that rotates according to the swing of the float, a magnetoelectric conversion element that faces the magnet, and an external lead terminal wired to the magnetoelectric conversion element. The magnetic flux of the magnet is changed according to the inclination angle that is the inclination angle, the magnetic field strength of the changing magnetic flux is detected by the magnetoelectric conversion element, converted into an electric signal, and sent to the external lead terminal to change the inclination angle. In a float pendulum type tilt angle sensor for non-contact detection, only one float is arranged vertically above the magnet and the magnetoelectric conversion element, and the external lead terminal is arranged vertically below the magnetoelectric conversion element. The float pendulum type tilt angle sensor is characterized in that the rotating shaft of is a bearing that receives a thrust load.

(2) The float pendulum type tilt angle sensor according to the above (1), wherein the float is entirely immersed in a liquid. (3) The float pendulum type tilt angle sensor according to the above (2), wherein the float has a size including a space in which a rotation axis is extended. (4) The float pendulum type tilt angle sensor according to the above (2), wherein one magnet is arranged substantially at the center of the rotation axis. (5) The float pendulum type tilt angle sensor according to the above (2), wherein the magnetoelectric conversion element is a Hall element.

[0014]

One float is arranged vertically above the magnet and the magnetoelectric conversion element, the external lead terminal is arranged vertically below the magnetoelectric conversion element, and the rotating shaft of the magnet is supported by the bearing that receives the thrust load. In addition, the entire float is immersed in the liquid, and the space in which the rotation axis is extended is included in the float. Further, one of the magnets is arranged substantially at the center on the rotation axis, and a Hall element is used as the magnetoelectric conversion element.

[0015]

Embodiments of the present invention in a non-contact type inclination angle sensor will be described in detail below with reference to the drawings. still,
The same parts in the above-mentioned conventional example are designated by the same reference numerals in the drawings, and detailed description thereof will be omitted. Figure 1
It is explanatory drawing explaining the 1st Example by this invention, FIG.1 (a) shows the front cross section, FIG.1 (b) is FIG.1 (a).
6 is a cross-sectional view of the side surface viewed from the direction of arrow vv in FIG. In FIG. 1A and FIG. 1B, the first
The main part of the embodiment is a first float 21 that floats in the liquid 8 and new rotary shafts 22 and 22 that rotate by the swing of the float 21, and the other parts are the same as those of the first conventional example in FIG. It is the same.

However, the magnet 3 and the magnetoelectric conversion element 4 are
The required function can be achieved by disposing one set on one side of the rotary shafts 22,22, but two sets may be provided on both sides of the rotary shafts 22,22 in order to increase the detection output. The first float 21 is made of a slightly elastic material such as a light alloy or a synthetic resin, and may be hollow or foamed to maintain its mechanical structure. Any material having a specific gravity slightly smaller than 8 may be used. The float 21 can apply a rotation torque based on the inclination angle θ to the rotation shafts 22 and 22 and maintain the orientation of the pendulum by the float 21 in the vertical direction.

According to experiments, the amount of drainage liquid of the float 21 is preferably about 1.5 times the weight of the portion including the magnet 3 and the like that operates like a pendulum, and if it is more than that, there is little effect.
The liquid 8 is preferably a liquid having a viscosity such as damping oil, but any liquid such as water or alcohol may be used. Since the entire first float 21 is immersed in the liquid 8, it is difficult to transmit minute vibrations, and the damping effect due to its viscosity is maximized so that the vibrations due to the rocking of the float 21 are converged. You can Moreover, vibration and expansion of the liquid 8 can be absorbed by the elasticity of the float 21.

The hysteresis of the rotation angle of the magnet 3 with respect to the tilt angle to be detected has the effect of improving from the conventional average of 1.5 ° to the average of 0.5 ° according to the present invention. As the magnetoelectric conversion element 4, it is preferable to use a hall element in order to realize the miniaturization of the whole, but a magnetoresistive element can also be used particularly for improving the detection accuracy. New rotary shaft 22,
Since the buoyant force of the first float 21 is slightly greater than the gravity, the thrust load (arrow) 23 generated in the direction of the rotating shaft 22 is indicated by 22.
It is possible to sufficiently reduce the load hanging on the bearings other than the above, and it is sufficient to support the thrust load (arrow) 23 by a known bearing. Further, in use, the first float 21 oscillates above the fulcrum of the pendulum due to buoyancy, and it is necessary to provide a detection means including the magnet 3 and the magnetoelectric conversion element 4 on the fulcrum. It is arranged vertically above the detection means.

Further, a plurality of lead wires 6 of the magnetoelectric conversion element 4 are provided.
.. 6 is protruding downward, so these lead wires 6 ...
It is possible to arrange the external lead terminals 5 to which the wires 6 are wired vertically below the detecting means. Therefore, the tilt angle sensor of the embodiment according to the present invention is shown in FIG.
1 side facing vertically upward, and eventually external lead terminals 5 ... 5
Can be mounted vertically on the component surface of the printed wiring board 9, and the lead wires 6 ... 6 can be taken out from the center thereof and wired to the external lead terminals 5 .. It will be possible to realize a tilt angle sensor with a natural structure.

2A and 2B are explanatory views for explaining a second embodiment according to the present invention. FIG. 2A shows a front cross section and FIG. 2B shows an arrow vi- in FIG. 2A. It is a cross-sectional view of a side surface viewed from the direction of vi. 2 (a) and 2
In (b), the main part of the second embodiment is a new arrangement of the second float 24, the magnet 3 and the magnetoelectric conversion element 4, and the other parts are the same as those of the second conventional example in FIG. . The second float 24 has a size including a space in which the rotary shafts 22, 22 are extended.

Therefore, first, the portion corresponding to the space where the rotary shafts 22, 22 are extended removes the load applied to the ball bearings of the rotary shafts 22, 22 to reduce friction. Second
In addition, by reducing this friction, the above-described rotational torque can be given to the rotating shafts 22 and 22 with high sensitivity, and the orientation of the pendulum by the float 24 can be maintained in the vertical direction even with a small buoyancy. The new arrangement of the magnet 3 and the magnetoelectric conversion element 4 is provided substantially in the center of the new rotary shaft 22 described above, so that the gravity and the rotary moment by the magnet 3 or the like with respect to the rotary shaft 22 are evenly distributed. Has become. It should be noted that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention.

[0022]

As described above, the present invention has the following effects. (1) Since the ball bearing and the magnetoresistive element which are expensive parts are not required, the overall product cost can be reduced. (2) Since the conventional weight is removed and a small float is used instead, the present invention can be applied to applications in which the overall size needs to be reduced. (3) Further, since the detection means is arranged vertically below the float, the inclination angle sensor itself can be mounted vertically above the component surface of the horizontal printed wiring board. Above (1),
Through (3), it is possible to provide a float pendulum type tilt angle sensor having an inexpensive structure suitable for mounting a printed wiring board.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a first embodiment according to the present invention.

FIG. 2 is an explanatory diagram illustrating a second embodiment according to the present invention.

FIG. 3 is an explanatory view schematically illustrating a conventional rotation axis orthogonal type tilt angle sensor.

FIG. 4 is an explanatory view schematically illustrating a conventional rotation axis parallel type tilt angle sensor.

FIG. 5 is an explanatory view schematically illustrating a conventional inclination angle sensor for a different casing.

[Explanation of symbols]

3 ... Magnet 4 ... Magnetoelectric conversion element 5 ... External lead terminal 6 ... Lead wire 7 ... Wiring board 8 ... Liquid 9 ... Printed wiring board 21 ... First Float 22 ... New rotation axis 23 ... Thrust load 24 ... Second float θ ... Inclination angle

Claims (5)

(57) [Claims] 1. A hollow float that floats in a liquid, a magnet supported by a rotating shaft that rotates according to the swing of the float, and a magnetoelectric conversion element that faces the magnet.
An external lead terminal wired to the magnetoelectric conversion element is provided, the magnetic flux of the magnet is changed according to the inclination angle which is the inclination angle, and the magnetic field strength of the changing magnetic flux is detected by the magnetoelectric conversion element and converted into an electric signal. In a float pendulum type tilt angle sensor that detects the tilt angle by sending to a lead terminal in a non-contact manner, the float has only one float and is arranged vertically above the magnet and the magnetoelectric conversion element, and the external lead terminal is A float pendulum type tilt angle sensor, which is arranged vertically below the magnetoelectric conversion element and in which the rotating shaft of the magnet receives a thrust load. 2. The float pendulum type tilt angle sensor according to claim 1, wherein the float is entirely immersed in a liquid. 3. The float pendulum type tilt angle sensor according to claim 2, wherein the float has a size including a space in which a rotation axis is extended. 4. The float pendulum type tilt angle sensor according to claim 2, wherein one magnet is arranged at substantially the center of the rotation axis. 5. The float pendulum type tilt angle sensor according to claim 2, wherein the magnetoelectric conversion element is a Hall element.